<template>
  <div class="todo-footer" v-show="total">
    <label>
      <input type="checkbox" v-model="isAll"/>
    </label>
    <span>
          <span>已完成{{ completedTodo }}</span> / 全部{{ total }}
        </span>
    <button class="btn btn-danger" @click="clearAllCompleted">清除已完成任务</button>
  </div>
</template>

<script>
export default {
  name: "UserFooter",
  props: ['todos'],
  data() {
    return {
    }
  },
  computed: {
    total:{
      get(){
        return this.todos.length
      }
    },
    completedTodo: {
      get() {
        return this.todos.reduce((pre, todo) => {
          return pre + (todo.completed ? 1 : 0)
        }, 0)
      },
      set(value) {
        //不写set 脚手架会报错
      }
    },
    isAll:{
      get(){
        return this.completedTodo === this.total
      },
      set(value) {
        this.$emit('checkAllTodo',value)
      }
    }
  },
  methods:{
    clearAllCompleted(){
      if(confirm("确定删除吗？")){
        this.$emit('clearCompletedTodo')
      }
    }
  }
}
</script>

<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>